Adherence of microorganisms to rat salivary pellicles

Numerous studies, using models to mimic the formation of the acquired pellicle, have concentrated on human saliva-coated hydroxyapatite; in contrast, although the rat is frequently used as an animal model, the information concerning the formation of pellicles from rat saliva is sparse. We compared the ability of Streptococcus and Actinomyces species to adhere to hydroxyapatite coated by rat saliva (rsHA) and human saliva (sHA). We also explored the influence of glucan synthesized in situ on the adherence of organisms. We show that each strain of organism has a distinct binding pattern, which was essentially the same with surfaces coated with either rat or human saliva. Dissolved rsHA beads revealed a major protein band (35-49 kD), identified as glutamine/glutamic-acid-rich protein; acidic proline-rich protein (31-45 kD and alpha-amylase (66 kD) were also identified. Overall, these in vitro data strongly suggest that the principles of bacterial adhesion to rsHA are similar to those observed with sHA.